Drugs online research references
Photodermatol Photoimmunol Photomed. 1997 Feb-Apr;13(1-2):27-36.
Use of dermal equivalent and skin equivalent models for identifying phototoxic compounds in vitro.
Augustin C, Collombel C, Damour O.
Laboratoire des Substituts Cutanes, (CNRS-UPR 412), Hopital Edouard Herriot, Lyon, France.
Phototoxicity inducing in vivo photoirritation, a reversible inflammatory reaction of the skin after chemical contact and UVA radiation exposure, is increasingly observed as a side effect associated with the use of both cosmetics and systemic drugs. In order to systematically screen for the phototoxic potential of new compounds, we propose two three-dimensional models suitable for in vitro testing: a dermal equivalent (DE) and a skin equivalent (SE) model. The DE model includes a collagen-glycosaminoglycans-chitosan porous matrix populated by normal human fibroblasts. The SE model is made by seeding normal human keratinocytes onto the DE, leading to a fully differentiated epidermis. The objectives of this pilot study are: 1) to compare the deleterious effects of UVA radiation on the two models and 2) to evaluate to what extent the in vitro results can predict the in vivo phototoxicity caused by well-known photoirritant compounds, included in the COLIPA validation phototoxicity reference chemical list. Dilutions of thiourea, sulisobenzone, promethazine, chlorpromazine and tetracycline were applied (20 microliters) onto DEs and SEs (n = 6) and incubated for 1 h (or 15 h) at 37 degrees C. Irradiated samples received 3 J/cm2 UVA. The 24 h post-irradiation residual cellular viability was measured using the MTT test on treated and untreated tissues and IL-1 alpha release measurement in collected SE culture media. A concordance in terms of photoirritant/non-photoirritant was obtained between the in vivo data and the in vitro results, suggesting that the DE and the SE models could be integrated, after a complete validation study, into a protocol for in vitro testing of the photoirritant potential of new molecules.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9361126&dopt=Abstract
J Pharm Sci. 1997 Nov;86(11):1234-8.
Ion-selective electrodes for promethazine determinations in pharmaceutical preparations and application to flow injection analysis.
Lima JL, Montenegro MC, Sales MG.
CEQUP/Departamento de Quimica-Fisica, Faculdade de Farmacia, Porto, Portugal.
The construction and evaluation of PM-selective electrodes with a conventional configuration and without internal reference solution are described. Two different PVC membranes were prepared with PM tetraphenylborate dissolved in 2-nitrophenyl octyl ether (type A) or bis (2-ethylhexyl)sebacate (type B). When the electrodes were evaluated in 0.01 M ionic strength solutions, both presented linear responses from 5 x 10(-5) to 1 x 10(-2) M, slopes close to the theoretical value, practical detection limits of approximately 2 x 10(-5) M, reproducibilities of +/- 0.2 mV/day, and a quick response (< 20 s). Using phosphate buffer solutions (pH 6.0), type B electrodes presented a lower practical detection limit and a better reproducibility than type A. Selectivity against several cations was assessed by the separated solutions method, and the type B electrodes were generally more selective. The type B membrane was also used for the construction of tubular electrodes for the automatic analysis of pharmaceutical products by flow injection analysis (FIA). These tubular detectors, evaluated in a low dispersion FIA system, presented better selectivity and sensitivity than the corresponding conventional ones. Several pharmaceutical preparations were analyzed with both conventional and tubular electrodes. The results obtained by FIA presented relative deviations of < 2% when compared with those obtained from the United States Pharmacopoeia monographs.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9383732&dopt=Abstract
J Pharm Biomed Anal. 1997 Oct;16(2):303-9.
Quantitation of promethazine enantiomers in human serum using a chiralcel OJ-R column and mixed-mode disc solid-phase extraction.
Liu J, Stewart JT.
Department of Medicinal Chemistry, College of Pharmacy, University of Georgia, Athens 30602-2352, USA.
A liquid chromatographic method was developed for the assay of R(+)- and S(-)-promethazine enantiomers from human serum. The method involves the use of the mixed mode disc solid-phase extraction technique for sample clean-up. Chromatographic resolution of the enantiomers was performed on a reversed-phase cellulose-based chiral column (Chiralcel OJ-R) under isocratic conditions using a mobile phase consisting of 0.5 M aqueous sodium perchlorate/acetonitrile (63:37, v/v) at a flow rate of 0.5 ml min-1. Recoveries in the range of 97-99% at 20 ng ml-1 levels were obtained for both promethazine enantiomers. Intra-day and inter-day precision calculated as R.S.D.% was in the 3-8% ranges for both enantiomers. Intra-day and inter-day accuracy calculated as percent error was in the 0-10 and 1-7% ranges for both enantiomers, respectively. Linear calibration curves were obtained for each enantiomer in serum in the concentration range 5-90 ng ml-1. The limit of quantitation of each enantiomer was 10 ng ml-1. The detection limit for each enantiomer in serum using UV detection at 249 nm was 2 ng ml-1 (S/N = 2).
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9408848&dopt=Abstract
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